1. Field of the Invention
The present invention relates to a display device for displaying various information such as character information, an image and a picture.
2. Description of the Related Art
Conventionally, a device disclosed in Japanese Patent Laid-Open No.6(1994)-262964 has been known as a display device for a vehicle use. The conventional display device is directed to display an image with an appearance of stereoscopy, and a screen on which display information is projected from a projector is designed to have a spherical surface, an elliptic curved surface or a concave curved surface.
However, in the case of a conventional display device, the projector emits only a projection light to be projected on a plane screen. If a distance between the projector and the screen is made to be shorter to reduce an arrangement space, the point of convergence does not coincide with a projection surface due to the curved surface of the projection surface of the screen. Thus, a projected image on the screen becomes out of focus at some portion of the screen, and a clear image cannot be displayed.
The image may be corrected by using an optical system to solve this problem. However, in such a case, a problem occurs that a necessary lens cannot be arranged because the space between the projector and the screen is too narrow. Even if it is possible, the cost of the device increases because the lens is required.
The object of the present invention is to provide a display device that projects display information from a plane element on a screen having a curved surface, in which every portion of a projected image does not be out of focus, a clear image can be projected without performing aberration correction by a complex optical system, and reduction of the size and the cost of the device can be achieved.
The display device of the present invention comprises: a light source; an image generator for outputting an image signal of an image to be displayed; and an image projector for processing light from the light source by use of the image signal outputted from the image generator and for projecting an image on the screen of a predetermined curved surface, and the image projector allows an aberration shape of an optical system on a projected image to be substantially coincide with the shape of a projection surface of the screen.
In the display device of the present invention, the light from the light source is processed by the image signal outputted from the image generator, and the image is projected on the screen of the predetermined curved surface. When the light from the light source is processed by use of the image signal, the aberration shape of the optical system on the projected image is processed so as to coincide with the shape of the projection surface of the screen. Accordingly, a desired image can be sharply projected on the screen of the curved surface. Therefore, according to the invention of claim 1, the image can be sharply projected on the screen having a complex curved surface, Moreover, the display device of a small size and a low cost can be provided without arranging a lens group for correcting the aberration of the optical system in the narrow space between the light source and the screen.